Dara Torres says there is one major difference between training for the Olympics in 2008 and getting prepped to make the U.S. Olympic swim team this year — hormones.

At 45, she is the oldest U.S. swimmer to show up at Olympic Trials, hoping to earn a berth to London. She’s not menopausal yet she says, but her dropping levels of hormones make it harder to recover after workouts.

“There are certain times when I can train really hard and I won’t break down as much,” she says. “There are other times when I have to take it easy. If my coach trains me too hard, it’ll be a much longer recovery for me to get back to where I need to be to have a good workout.”

Not that you can tell by looking at her. With sculpted arms and famously defined abs (people have stopped her on the street and asked for a peek), Torres looks like the women half her age with whom she trains. If she makes the team, she will be the first U.S. swimmer to make a splash at six Olympic Games (that’s a span of 24 years) and her twelve Olympic medals tie the all-time medal record for a female swimmer with Jenny Thompson.

She logs in nearly two hours of swimming five days a week at the Coral Gables, Fla. facility where she trains, and maintains an intense gym regimen that includes resistance stretching for two hours every other day. (The resistance not only stretches muscles but flexes them at the same time, improving recovery and maintaining tone.) To control those fluctuating hormones, she works with a naturopath to keep her levels productive — and legal.

But being the oldest swimmer at Olympic Trials, which conclude on Sunday in Omaha, Nebraska, also means that she can’t do as much as the younger swimmers. In Beijing four years ago, Torres qualified for both the 50m and 100m freestyle, but dropped the 100m event. This time, she has decided to focus only on making the team for the 50m event (she won silver in the event in 2008). “People say they don’t know why I’m doing that because they take the top six in the 100m free, and only the top two in the 50m free, so I have a better chance in the 100 m,” she says. “But I can barely swim three races [including the final and two qualifying heats] for one event, let alone for two.”

And it’s not the only concession she has made in her bid for London. While training for Beijing, she put off much needed shoulder surgery, and the year after the Games, she learned she would need reconstructive knee surgery. “My knee was pretty messed up,” she says. “I couldn’t bend down to pick my daughter up, and I couldn’t walk up and down stairs without holding on to the railing.” The recovery was long and slow — nearly two years — which tried Torres’ patience. “I’m used to having surgery and a few weeks later, I’m ready to go. But this wasn’t like that. I had to follow the doctor’s guidelines or it wasn’t going to take. That was a challenge for me, and what tested me the most.”

Nearing the end of her recovery in 2010, Torres had lunch with her coach, Michael Lohberg, who had guided her through her last Olympics from a hospital bed at the National Institutes of Health, where he was being treated for aplastic anemia. “I didn’t bring it up, but he said ‘When are we going to do this again? When are we going to go to another Olympics? Let’s just do it.”

It took Torres a year and a half to put on the 10 pounds of muscle she now relies on to power through the training, and that she hopes will fuel her “splash and dash,” as the 50m race is known, at Trials. Lohberg has since passed away, but Torres continues to honor his memory. “I know he would want me to continue on this path, and do the best I can, and see what happens,” she says.

She admits she has more bad workouts than good ones, but this time around, it’s about overcoming those bad days and realizing there will be better ones. “I look at the younger kids and I wish I were like them, and look at the way they bounce back, and come back to another workout later, when all I want to do is take a nap because I’m so tired,” she says. “But you have to overcome that, and be like, ‘okay, I’ll feel better the next day.’ That’s the mentality you have to have in order to get through it.”

That, and reminding herself that she no longer has anything to prove as far as her swimming career is concerned. “My inspiration comes from people who come up to me and tell me their stories,” she says. “So I figure if I do this one more time at age 45, overcoming reconstructive knee surgery, and trying to overcome being a middle-age Olympian, if I can do something that helps more people to find balance between what they love to do and aging, then that’s what inspires me.”

Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny . You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.